The list of supplements that claimed to increase or improve fat metabolism is long. The most popular supplements include caffeine, carnitine, green tea, conjugated linoleic acid, and chromium  . Best Healthiest Fat Burner Supplement: Top 7  Fat burners contain herbal ingredients such as ephedrine, yohimbine, chitosan, and pyruvate , all of which operate on the principle of thermogenesis to increase energy, stimulate the metabolism, and/or suppress the appetite  .

In this review, the evidence for some of these supplements is briefly summarized. Based on the available literature, caffeine and green tea have data to back up its fat metabolism-enhancing properties. For many other supplements, although some show some promise, evidence is lacking. The list of supplements is industry-driven and is likely to grow at a rate that is not matched by a similar increase in scientific underpinning.

1. Caffeine is found in coffee, tea, soft drinks, cocoa, and cola nut. It has been most widely used in fat-loss products  . Caffeine is not only an energy enhancer but it is also becoming a popular fat loss supplement and workout performance booster  . Many published studies are documenting its effectiveness at weight loss and reducing body fat  . These studies have shown that caffeine is capable of increasing the release of stored fat, as well as the rate at which calories are burned. The effects of caffeine are best realized when used in combination with other supplements. 12 Popular Effective Fat Burning Supplements of 2022 The most popular combinations have been the ephedrine/caffeine/yohimbine in ECY stack and ephedrine/caffeine/aspirin in ECA stack  . Caffeine promotes fat loss at two major sites: fat cells and muscle cells. The action of caffeine at the fat cell appears to be supportive of the fat loss signal generated by neurotransmitters and drugs that stimulate β-adrenergic receptors  . These receptors are stimulated by adrenalin and similar chemicals. The level of adrenalin-like drugs, hormones, and neurotransmitters released at any point in time is called the “sympathetic tone.” The sympathetic tone may rise quite high during a “fight-or-flight” response or it may be low during periods of rest or sleep  . At rest and without the addition of caffeine, there is not much fat release or increase in calorie burning because of the effect of a competing class of adrenergic receptors, A2-adrenergic receptors  . While β-receptors promote fat loss and increase calorie burning, the A2-receptors do the opposite  .

2. Green tea extract contains catechin epigallocatechin-3-gallate (EGCG), the active ingredient   that may help boost the metabolic rate by stimulating the metabolism, helping the body to burn more calories, and may possibly lead to weight loss  . It was discovered that EGCG inhibits catechol-O-methyltransferase, an enzyme that breaks down norepinephrine. The higher levels of norepinephrine in the body enhance the overall rate of fat loss by stimulating the release of fatty acids from fat cells into the bloodstream for burning as fuel  . Researchers examined the effects of green tea on weight loss in obese men and women. What Fat Burning Supplements For Athletes. Participants followed a diet plan with green tea or a placebo for 12 weeks. Energy expenditure and fat oxidation, or fat burning, were measured at the beginning of the study and during weeks 4, 8, and 12. Scientists observed that the green tea group lost more body fat compared to the placebo group  .